The Liberal Democrats’ entry into government has left the party unable to compete, for the first time in modern history, for the protest vote. (See the Barnsley result.)

The collapse of the BNP into a mass of squabbling factions, and its persistent legal and financial troubles, means that it’s a far less effective bidder for both the protest vote and anti-politics vote. (See the Barnsley result again.)

This leaves UKIP as the main contender for both in England. Farage seems to me to be a classic “marmite” politician – the kind one either loves or hates. For bigger parties, this would be a problem. For UKIP, as it attempts to define itself, this aspect of their party’s leadership is probably a net plus. Farage fought a curiously lacklustre general election campaign against John Bercow (before that horrible plane crash). But he’s an experienced campaigner who appreciates that UKIP needs to be more than a single issue party if it’s to win more support. I’m curious to see how he plans to do so, since there are signs that he’s uncomfortable with the stress that Malcolm Pearson put on unambiguous – and inflammatory – anti-Islam campaigning.

So then: UKIP’s well placed to mop up more protest and anti-politics votes. But does it pose a special threat to the Conservative Party and, if so, what should David Cameron’s response be?To answer those questions, it’s obviously important to work out where UKIP’s votes come from in the first place.

One school of thought stresses that UKIP’s “core vote” is made up of anti-politics and protest voters. That’s essentially the suggestion of research carried out by James Bethell.

A further view, set out by Dennis Kavanagh and Philip Cowley in their “The British general election of 2010”, is that “the party’s baseline vote does come disproportionately from those that vote Conservative”.

The latter note that the increase in the share of the vote in seats that UKIP contested in 2010, but not in 2005, rose by less than the national average of the Conservative vote. Recent Angus Reid data suggests that former Tory voters may now be switching to Farage’s party.Post-Barnsley analysis claims that 29 per cent of UKIP by-election voters previously supported Labour, while only 19 per cent had backed the Conservatives. However, the bulk of the evidence suggests that to date UKIP has tended to draw more from the Tories than Labour.So how should David Cameron respond? The study that’s looked at UKIP voters in most detail appears to be Bethell’s, which found that –

“Surprisingly, perhaps, immigration is a higher priority for UKIP voters even than the issue of Europe, which comes in third. This was reflected in the focus groups we conducted. When asked why they voted UKIP, all of the participants said because UKIP was opposed to immigration. They were interested in the issue of Europe but they did not volunteer this as a key factor in deciding their vote. One of the intriguing things from the focus groups, however, was the feeling that people are not necessarily voting for UKIP on immigration because they understand that free movement of labour across the EU leads to high levels of immigration. Many seem to vote UKIP simply because they think UKIP is opposed to immigration, which is a slightly different motivation. In other words, not everyone makes the intellectual leap that withdrawal from the EU would likely lead to a significant drop in immigration.”

So my view’s as follows –

Making a special pitch for UKIP voters wouldn’t work for many of them. Bethell’s research suggests that some of the “anti-voters” of which UKIP voters are a part will no longer heed the mainstream parties.

However, ignoring UKIP voters is risky too. This is because Bethell’s research also finds that not all UKIP voters are permanently alienated from the mainstream parties. If UKIP’s support continues to grow – as it can reasonably be expected to do – the shortcomings of a modernisation strategy which exclusively pursues better off and liberally inclined voters will become more apparent.

The key issue for UKIP voters is immigration. If the Government lasts its full term, it needs to be able to point to success at the end of it in allieviating pressure on housing, schools, hospitals, transport and public services. Bringing non-EU immigration down to the “tens of thousands” is therefore essential. As for EU immigration, Ministers should be examining the radical ideas that have been floated by Nick Boles.